This invention relates to imaging x-ray emission spectroscopy and more particularly to the accurate characterization or calibration methods applied to bent crystals, such as quartz crystals, that are used as a part of an in-situ x-ray imaging diagnostic system, such as in a fusion reactor that produces an x-ray emitting plasma.
Spherically and toroidally bent crystals are used as gratings for measuring narrow-bandwidth, two dimensional x-ray images. These crystals are often used for imaging laser plasma x-ray emission with high resolution. The brightness and spectral bandwidth of the resulting x-ray images are fundamentally determined by the wavelength dependent instrument function of the crystal. Additional limits on brightness, spectral bandwidth, field of view and spatial resolution are introduced by the set-up geometry. When imaging narrow-bandwidth x-ray lines, spherically and toroidally bent crystals may provide higher spectral and spatial resolution than other x-ray imaging instruments, such as pinhole cameras or metal-mirror Kirkpatrick-Baez microscopes. Quantitative x-ray imaging involves characterization of the crystal spectrometric properties and imaging performance so that the instrumentation is properly calibrated. Due to extreme selectivity of the imaging technique, lack of calibration leads to false or even no output results.
Despite the advances made in the field of x-ray imaging of laser-generated plasma, there is a need in the art to provide a more accurate and reliable method for characterizing a quartz crystal used for X-ray imaging of laser-generated plasmas.